Frederick and John Allen show up on the Beaufort Co. 1820 Federal census. Frederick moved to Williamson Co., So. IL at some point in the 1830s-1840s. Randall B. Allen, along with the rest of Frederick's children went with Frederick to So. Illinois and died there. (Randall died in Williamson Co.)

I can give you more details if you want to e-mail me. Do you have more information on this individual "Nettie Allen"? I only have a name - "Hettie Nannie Allen" and no information on a spouse. It is possible they are the same individual.